Method for operating a fuel cell system, and a control device

Abstract

The invention relates to a method for operating a fuel cell system, wherein hydrogen-containing anode gas exiting at least one fuel cell is recirculated via an anode circuit ( 1 ), wherein liquid water ( 2 ) contained in the anode gas is separated with the aid of a water separator ( 3 ) integrated into the anode circuit ( 1 ), is collected in a container ( 4 ), and is removed from the container ( 4 ) by opening a drain valve ( 5 ), and the anode circuit ( 1 ) is flushed by opening a purge valve ( 6 ) integrated into the container ( 4 ) of the water separator ( 3 ), wherein the hydrogen content is measured with the aid of a hydrogen sensor ( 7 ) connected downstream of the purge valve ( 6 ). According to the invention, when the purge valve ( 6 ) is open and a delayed increase in the hydrogen content is detected with the aid of the hydrogen sensor ( 7 ), the “container full” state is detected. The invention also relates to a control device ( 8 ) for carrying out the method or individual method steps.

1 . A method for operating a fuel cell system, wherein hydrogen-containing anode gas exiting at least one fuel cell is recirculated via an anode circuit ( 1 ), wherein liquid water ( 2 ) contained in the anode gas is separated via a water separator ( 3 ) integrated into the anode circuit ( 1 ), is collected in a container ( 4 ), and is removed from the container ( 4 ) by opening a drain valve ( 5 ), and the anode circuit ( 1 ) is flushed by opening a purge valve ( 6 ) integrated into the container ( 4 ) of the water separator ( 3 ), wherein the hydrogen content is measured via a hydrogen sensor ( 7 ) connected downstream of the purge valve ( 6 ),
 wherein when the purge valve ( 6 ) is open and a delayed increase in the hydrogen content is detected via the hydrogen sensor ( 7 ), the “container full” state is detected.   
     
     
         2 . The method according to  claim 1 , wherein the information “container full” is used to calibrate a model which is used to determine the amount of water in the container ( 4 ). 
     
     
         3 . The method according to  claim 1 , wherein the measurement signals of the hydrogen sensor ( 7 ) are transmitted for evaluation to a control device ( 8 ), via which the purge valve ( 6 ) is actuated. 
     
     
         4 . The method according to  claim 1 ,
 wherein the drain valve ( 5 ) is activated and opened when the “container full” state is detected.   
     
     
         5 . A control device ( 8 ) configured to perform steps of the method according to  claim 1 .